The invention relates to a servo drive for activating a tailgate of a motor vehicle. Servo drives for activating tailgates of motor vehicles are known. For example, EP 1 108 846 A2 describes a pivoting door drive, which has a drive device. This drive device is of structurally complex design to such an extent that during operation a relatively large installation space is necessary, which is not available in many cases. In other known servo drives, pivotable ring gear segments are used which generally require, for operation, an installation space which, in the vicinity of the drive unit, must correspond in extent at least to the entire external diameter of the ring gear segment. However, this installation space is also often not available.